ios - 如何使用 NSNotificationCenter 在类之间传递对象 - 传递对象失败

Question

我的代码:

NSDictionary *dict = @{@"1": @"_infoView3",
                       @"2": [NSNumber numberWithFloat:_showSelectionView.frame.size.height]
                       };

[[NSNotificationCenter defaultCenter] addObserver:self
                                         selector:@selector(keyboardWillShow:)
                                             name:@"UIKeyboardWillShowNotification"
                                           object:dict];

[[NSNotificationCenter defaultCenter] addObserver:self
                                         selector:@selector(keyboardDidHide:)
                                             name:@"UIKeyboardDidHideNotification"
                                           object:dict];

和:

- (void) keyboardWillShow:(NSNotification *)note {
    NSDictionary *userInfo = [note userInfo];
    CGSize kbSize = [[userInfo objectForKey:UIKeyboardFrameBeginUserInfoKey] CGRectValue].size;

    // move the view up by 30 pts
    CGRect frame = self.view.frame;
    frame.origin.y = -kbSize.height;

    [UIView animateWithDuration:0.3 animations:^{
        self.view.frame = frame;
    }];
}

- (void) keyboardDidHide:(NSNotification *)note {

    // move the view back to the origin
    CGRect frame = self.view.frame;
    frame.origin.y = 0;

    [UIView animateWithDuration:0.3 animations:^{
        self.view.frame = frame;
    }];
}

但是当键盘显示或隐藏时，这两种方法都不起作用。如果我传递对象 nil 而不是 dict，这两种方法就可以工作。

不知道哪里出了问题，求大神指点，谢谢

Answer 1

正如我所看到的，您正在尝试在观察者端发布对象。恰恰相反，请参见下面的示例。

接收类

- (void)viewDidLoad {
    [[NSNotificationCenter defaultCenter] addObserver:self
        selector:@selector(receiveNotification:) 
        name:@"myNotification"
        object:nil];
}

- (void)receiveNotification:(NSNotification *)notification
{
    if ([[notification name] isEqualToString:@"myNotification"]) {
        NSDictionary *myDictionary = (NSDictionary *)notification.object;
        //doSomething here.
    }
}

发送者类

- (void)sendNotification {
    [[NSNotificationCenter defaultCenter] postNotificationName:@"myNotification" object:YOUR_DICTIONARY];
}